Resistance pressure weld for nuclear reactor fuel rod tube end plug

Abstract

A fuel rod for a nuclear reactor, including a cladding tube having a first end with an annular end face, a second end with an annular end face, and a cylindrical body portion extending therebetween, and a first tube end plug including a front portion, an annular lip with an annular end face, and a substantially straight cylindrical body portion extending therebetween, wherein the surface area of the annular end face of the first end of the cladding tube and the annular end face of the annular lip of the first tube end plug are substantially equal, and the annular end face of the first end of the cladding tube and the annular end face of the annular lip of the first tube end plug are connected by a resistance pressure weld.

What is claimed is: 
     
       1. A method of performing a resistance pressure weld for a nuclear fuel rod, comprising the steps of:
 providing a cladding tube having a first end with an annular end face; 
 providing a tube end plug including a front portion, a rear face, a cylindrical body portion extending therebetween, and an annular undercut extending from the rear face into the cylindrical body portion, thereby forming an annular lip having an annular end face; 
 securing a first electrode to the first end of the cladding tube; 
 securing a second electrode to the tube end plug; 
 abutting the annular end face of the cladding tube to the annular end face of the tube end plug; 
 applying compressive force to both the cladding tube and the tube end plug; and 
 applying a direct electric current between the first and the second electrodes so that current flows between the cladding tube and the tube end plug, 
 wherein the bottom wall of the annular undercut defines a continuous curve in a plane that both includes a longitudinal center axis of, and bisects, the tube end plug. 
 
     
     
       2. The method of  claim 1 , wherein the continuous curve of the annular undercut has a semi-circular cross-section having a constant radius of curvature. 
     
     
       3. A method of performing a resistance pressure weld for a nuclear fuel rod, comprising the steps of:
 providing a cladding tube having a first end with an annular end face; 
 providing a tube end plug including a front portion, a rear face, a cylindrical body portion extending therebetween, and an annular undercut extending from the rear face into the cylindrical body portion, thereby forming an annular lip having an annular end face; 
 securing a first electrode to the first end of the cladding tube; 
 securing a second electrode to the tube end plug; 
 abutting the annular end face of the cladding tube to the annular end face of the tube end plug; 
 applying compressive force to both the cladding tube and the tube end plug; and 
 applying electric current between the first and the second electrodes so that current flows between the cladding tube and the tube end plug, 
 wherein the bottom wall of the annular undercut defines a continuous curve in a plane that both includes a longitudinal center axis of, and bisects, the tube end plug. 
 
     
     
       4. The method of  claim 3 , wherein the electric current applied between the first and the second electrodes is a direct current. 
     
     
       5. The method of  claim 3 , wherein the continuous curve of the annular undercut has a semi-circular cross-section having a constant radius of curvature.